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Showing papers on "Methyl vinyl ketone published in 2005"


Journal ArticleDOI
TL;DR: An effective bifunctional Lewis base and Bronsted acid phosphine Lewis base system has been disclosed in this catalytic, asymmetric aza-Baylis-Hillman reaction and the mechanistic insight has been investigated by 31P and 1H NMR spectroscopic measurements.
Abstract: In the aza-Baylis-Hillman reaction of N-sulfonated imines (N-arylmethylidene-4-methylbenzenesulfonamides and others) with methyl vinyl ketone, ethyl vinyl ketone, and acrolein, we found that, in the presence of a catalytic amount of chiral phosphine Lewis base such as (R)-2'-diphenylphosphanyl-[1,1']binaphthalenyl-2-ol LB1 (10 mol %) and molecular sieve 4A, the corresponding aza-Baylis-Hillman adducts could be obtained in good yields with good to high ee (70-95% ee) at low temperature (approximately -30 to -20 degrees C) or at room temperature in THF, respectively. In CH2Cl2 upon heating at 40 degrees C, the aza-Baylis-Hillman reaction of N-sulfonated imines with phenyl acrylate or naphthyl acrylate gave the adducts in good to high yields (60-97%) with moderate ee (52-77%). The mechanistic insight has been investigated by 31P and 1H NMR spectroscopic measurements. The key enolate intermediate, which has been stabilized by intramolecular hydrogen bonding, has been observed by 31P and 1H NMR spectroscopy. An effective bifunctional Lewis base and Bronsted acid phosphine Lewis base system has been disclosed in this catalytic, asymmetric aza-Baylis-Hillman reaction.

303 citations


Journal ArticleDOI
TL;DR: An effective bifunctional chiral nitrogen Lewis base-Brønsted acid system has been revealed in this type of aza-Baylis-Hillman reaction and the first such reaction of 1 with the simplest Michael acceptor MVK and methyl acrylate has been achieved with excellent enantioselectivity.
Abstract: The chiral nitrogen Lewis base, tricyclic cinchona alkaloid derivative TQO, is an effective promoter in the catalytic, asymmetric aza-Baylis-Hillman reaction of N-sulfonated imines Ar-CH=NR' 1 (R' = Ts, Ms, Ns, SES) with various activated olefins such as methyl vinyl ketone (MVK), ethyl vinyl ketone (EVK), acrolein, methyl acrylate, phenyl acrylate, or alpha-naphthyl acrylate to give the corresponding adducts in moderate to good yields with good to high ee (up to 99%) at -30 degrees C or 45 degrees C in various solvents, including DMF/MeCN (1:1, v/v). The first such reaction of 1 with the simplest Michael acceptor MVK and methyl acrylate has been achieved with excellent enantioselectivity. The adducts derived from MVK and EVK had the opposite absolute configuration to those from acrolein, methyl acrylate, phenyl acrylate, and alpha-naphthyl acrylate. A plausible mechanism has been proposed on the basis of previous reports and the authors' investigations. An effective bifunctional chiral nitrogen Lewis base-Bronsted acid system has been revealed in this type of aza-Baylis-Hillman reaction.

112 citations


Journal ArticleDOI
TL;DR: A direct catalytic asymmetric aldol reaction of methyl vinyl ketone is described using the dinuclear zinc catalyst, which results in a obtained a Aldol adduct that functions as a bifunctional building block by utilization of the vinyl functionality.
Abstract: A direct catalytic asymmetric aldol reaction of methyl vinyl ketone is described using our dinuclear zinc catalyst. The obtained aldol adduct functions as a bifunctional building block by utilization of the vinyl functionality. For example, convergent fragment coupling methods have been demonstrated via highly diastereoselective cycloaddition of nitrile oxide after reduction into 1,3-diol or via cross-metathesis reaction.

99 citations


Journal ArticleDOI
TL;DR: The dihydride-dihydrogen complex [OsH2(η5-C5H5)(η2-H2)(PiPr3)]BF4 (2) has been prepared by addition of HBF4·OEt2 to OsH3( η5c5h5) and PiPr3.

77 citations


Journal ArticleDOI
TL;DR: The results indicate that the hydrogen-bond formation between chloroform and the carbonyl oxygen of the o-QM lowers the activation energies and increases the asynchronicity and the discussions for the charge distribution and charge transfer on different transition states indicate that there are different molecular mechanisms for the different substituted ethenes.
Abstract: The Diels-Alder (DA) reactions of various substituted ethenes (methyl vinyl ether (MVE), styrene, and methyl vinyl ketone (MVK)) with o-quinone methides (o-QM) are studied by means of density functional theory (DFT) at the B3LYP/6-31G(d,p) level. On the basis of analysis for frontier molecular orbital and comparison of the activation energies for different reaction pathways, the ortho attack modes present transition structures more stable than the meta ones. The reactivity, ortho selectivity, and asynchronicity are enhanced with the increase of the electron-releasing character of the substitute on ethene fragment. The discussions for the charge distribution and charge transfer on different transition states indicate that there are different molecular mechanisms for the different substituted ethenes. The calculations show that the effect of solvent decreases the activation energy and increases the asynchronicity. The results also indicate that the hydrogen-bond formation between chloroform and the carbonyl oxygen of the o-QM lowers the activation energies and increases the asynchronicity.

65 citations


Journal ArticleDOI
TL;DR: In this paper, aza-Morita-BaylisHillman reaction of N-sulfonated imines (N-arylmethylidene-4-methylbenzenesulfonamides and others) with methyl vinyl ketone (MVK) was investigated.
Abstract: In the aza-Morita–BaylisHillman reaction of N-sulfonated imines (N-arylmethylidene-4-methylbenzenesulfonamides and others) with methyl vinyl ketone (MVK), we found that in the presence of a catalytic amount of the chiral phosphine Lewis bases (R)-(−)-6,6′-bis[tris(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl)silyl]-2′-(diphenylphosphanyl)-[1,1′]binaphthalenyl-2-ol LB2 and (R)-(−)-6,6′-(3,3,4,4,5, 5,6,6,7,7,8,8,8-tridecafluorooctyl) -2′-(diphenylphosphanyl)-[1,1′]binaphthalenyl-2-ol LB3 bearing two perfluoroalkane chains at 6,6′-positions of the naphthalene framework, the corresponding adducts could be obtained in good yields with good to high ee (52–95% ee) at room temperature (15 °C) or low temperature (−20 °C) in THF, respectively. LB3 is more effective in this reaction than the previously reported original chiral phosphine Lewis base (R)-(−)-2′-diphenylphosphanyl-[1,1′]binaphthalenyl-2-ol LB1.

55 citations


Journal ArticleDOI
TL;DR: In this paper, the authors used a pulsed laser photolysis-laser induced fluorescence (PLP-LIF) technique to investigate the kinetics of the reaction of OH radicals with 2,4-pentanedione and 3-methyl-2,4,pentanedion.
Abstract: The kinetics of the reaction of OH radicals with 2,4-pentanedione and 3-methyl-2,4-pentanedione have been investigated in the gas-phase using a pulsed laser photolysis-laser induced fluorescence (PLP-LIF) technique. Hydroxyl radicals were generated from the parent compounds following pulsed laser photolysis at 248 nm. The rate coefficients were also determined using a conventional relative rate method. Average values of the bimolecular rate coefficients of k (OH + CH 3 C(O)CH C(OH)CH 3 ) = (8.78 ± 0.58) × 10 −11 , k (OH + CH 3 C(O)C(CH 3 ) C(OH)CH 3 ) = (6.06 ± 0.54) × 10 −11 and k (OH + CH 3 C(O)CH(CH 3 )C(O)CH 3 ) = (1.16 ± 0.09) × 10 −11 cm 3 (molecule s) −1 were determined at 298 ± 2 K. Rate coefficients for the reaction of OH radicals with allyl alcohol and methyl vinyl ketone were also determined at 298 ± 2 K using the PLP-LIF technique employing the photolysis of 2,4-pentanedione and 3-methyl-2,4-pentanedione as the OH radical sources respectively, k (OH + CH 2 CHCH 2 OH) = (4.60 ± 0.19) × 10 −11 and k (OH + CH 2 CHC(O)CH 3 ) = (1.86 ± 0.12) × 10 −11 cm 3 (molecule s) −1 . The measured rate coefficients are used to derive tropospheric lifetimes for the compounds.

42 citations


Journal ArticleDOI
TL;DR: Results suggest that under low NOx conditions reactions of some of the hydroperoxides and hydroxycarbonyls produced from the OH-initiated oxidation of isoprene may be a significant source of methyl vinyl ketone and 3-methylfuran in the atmosphere.
Abstract: A novel technique has been developed to simultaneously monitor the kinetics of the OH radical-initiated oxidation of isoprene and formation and oxidation of its products (methyl vinyl ketone, methacrolein, 3-methylfuran, and formaldehyde) using online mass spectrometry. The kinetics of isoprene and its products were investigated at 323 K and at 1 atm total pressure. The responses of 30 representative ions for isoprene and its products were monitored during the reaction, and their concentration profiles were calculated by linear algebraic equations, which resolve the measured mass spectra of representative ions into the responses of individual target organics, and by calibrations, which converted the responses to individual target concentrations. Using this method, yields of methyl vinyl ketone, methacrolein, and 3-methylfuran at 323 K were measured to be 14.4 ± 0.1%, 19.0 ± 0.2%, and 2.9 ± 0.2%, respectively, in excellent agreement with previously reported yields under NOx-free conditions. The reaction ki...

42 citations


Journal ArticleDOI
TL;DR: In this article, cross-metathesis reactions between 1,3-dienes and electron-deficient olefins have been investigated and Methyl vinyl ketone as the coupling partner was shown to provide the best yields.

42 citations


Journal ArticleDOI
TL;DR: Using polystyrene-supported benzoquinone (PS-BQ) as cocatalyst with palladium chloride, the acetalization of terminal olefins with electron-withdrawing groups, i.e., acrylate esters, acrylonitrile, methyl vinyl ketone and acrolein, was carried out smoothly in supercritical carbon dioxide under oxygen atmosphere as discussed by the authors.

39 citations


Journal ArticleDOI
TL;DR: In this article, 1.2BF3-substituted 1,3-butadienes with potassium and tetrabutylammonium counterions have been prepared in gram quantities from chloroprene via a simple synthetic procedure.

Journal ArticleDOI
TL;DR: Cyano(dialkylamino)boryl ethers of homopropargylic alcohols undergo intramolecular addition of a B-CN bond across their carbon-carbon triple bonds (cyanoboration) in the presence of palladium and nickel catalysts as discussed by the authors.

Journal ArticleDOI
TL;DR: The rate constant and product ion distribution of the reactions of H 3 O +, NO + and O 2 + with methyl vinyl ketone (MVK), methacrolein (MaCR), pivaldehyde, 2-methyl-butanal, glyoxal, o -, m - and p -tolualdehyde have been investigated at 150 and 297 K using a selected ion flow tube (SIFT) as discussed by the authors.

Journal ArticleDOI
TL;DR: In mouse hepatocytes, the two compounds exhibited very comparable abilities to induce rapid, concentration-dependent cell death as well as protein carbonylation, suggesting that the acute toxicity of short-chain alpha,beta-unsaturated carbonyl compounds involves their ability to form acyclic Michael addition adducts rather than Schiff conjugates or heterocyclic adduct
Abstract: Acrolein is a highly toxic environmental pollutant that readily alkylates the e-amino group of lysine residues in proteins. In model systems, such chemistry involves sequential addition of two acrolein molecules to a given nitrogen, forming bis-Michael-adducted species that undergo aldol condensation and dehydration to form Ne-(3-formyl-3,4-dehydropiperidino)lysine. Whether this ability to form cyclic adducts participates in the toxicity of acrolein is unknown. To address this issue, we compared the chemistry of protein adduction by acrolein to that of its close structural analogue methyl vinyl ketone, expecting that the α-methyl group would hinder the intramolecular cyclization of any bis-adducted species formed by methyl vinyl ketone. Both acrolein and methyl vinyl ketone displayed comparable protein carbonylating activity during in vitro studies with the model protein bovine serum albumin, confirming the α,β,-unsaturated bond of both compounds is an efficient Michael acceptor for protein nucleophiles. ...

Journal ArticleDOI
TL;DR: In this paper, the (Z)-N-substituted 4-methylene-5-propylidene-2-oxazolidinone dienes were prepared by a one-step synthesis, starting from 2,3-hexanedione and isocyanates.
Abstract: The (Z)-N-substituted 4-methylene-5-propylidene-2-oxazolidinone dienes were prepared by a one-step synthesis, starting from 2,3-hexanedione and isocyanates. Diels-Alder cycloadditions of these dienes were carried out in the presence of the dienophiles methyl vinyl ketone, methyl propiolate, and a captodative olefin, under conditions such as solvents of high polarity, Lewis acid catalysis, and non-conventional energy sources. The reactions carried out either with mixtures of H2O/MeOH or under BF3·Et2O catalysis yielded the highest regio- and stereoselectivities. The use of ionic liquids, microwaves, and ultrasound did not significantly increase the selectivity.

Journal ArticleDOI
TL;DR: In this paper, the Baylis-Hillman adducts of alkyl vinyl ketones were used to synthesize polysubstituted quinolines, which were then used in a mixed solvent system of PPA and 1,2-dichloroethane.
Abstract: Recently, we have reported a variety of chemical transformations of the Baylis-Hillman adducts into useful heterocyclic compounds. Very recently, we published the synthesis of 3-benzylquinolin-2-ols from the Baylis-Hillman adducts of ethyl acrylate bearing aniline moiety at the secondary position. 3-Benzylquinolin-2-ols could be formed via the sequential aza-Claisen rearrangement of the adduct in PPA, amide bond formation, and the following isomerization with the aid of DBU as shown in Scheme 1. In this paper we would like to report our results on the synthesis of polysubstituted quinolines from the BaylisHillman adducts of alkyl vinyl ketones. As exemplified in Scheme 2, the required starting materials 2 were synthesized from the acetates of the Baylis-Hillman adducts of methyl vinyl ketone and ethyl vinyl ketone via the corresponding DABCO salts according to the reported procedure. In the reaction, however, cinnamyl amine derivatives 3 were isolated in variable yields (6-37%) depending upon the nature of anilines (Table 1) as side products. The formation of primary adducts 3 from 2 under the reaction conditions can be explained by sequential addition and elimination of aniline, presumably due to the higher electrophilicity of the β-carbon (marked with asterisk) of 2 than the cases of ethyl acrylate (Scheme 1). As can be seen easily in the ratios of 2 and 3 (Table 1), the amounts of primary products 3 were gradually increased according to the increase of the nucleophilicity of anilines. With the compound 2a in hand we examined the reaction in PPA at various reaction temperatures. Mixed solvent system of PPA and 1,2-dichloroethane was used in order to

Journal ArticleDOI
TL;DR: (R)-2-[(S)-1-hydroxymethyl-2-phenylethylimino]-4-phenylimidazolidine was newly prepared from (R)-phenylglycine as the key functional unit of these guanidines, leading to expected asymmetric induction in the Michael adduct with moderate enantioselectivity in the use of the latter polymeric chiral guanids.
Abstract: Polymer-supported and polymeric chiral guanidines carrying an imidazolidine skeleton are designed as polymer-based base catalysts. Thus, (R)-2-[(S)-1-hydroxymethyl-2-phenylethylimino]-4-phenylimidazolidine was newly prepared from (R)-phenylglycine as the key functional unit of these guanidines. Application of the polymer-based chiral guanidines to the asymmetric Michael reaction of t-butyl diphenyliminoacetate with MVK led to expected asymmetric induction in the Michael adduct with moderate enantioselectivity in the use of the latter polymeric chiral guanidines.

Journal ArticleDOI
TL;DR: In this article, the Baylis-Hillman reaction of various aryl aldehydes with methyl vinyl ketone and acrylonitrile in the thermomorphic binary system (DMF/cyclohexane, 1/1, v/v) has been investigated.
Abstract: The Baylis–Hillman reaction of various aryl aldehydes with methyl vinyl ketone and acrylonitrile in the thermomorphic binary system (DMF/cyclohexane, 1/1, v/v) has been investigated. The phase selectively soluble alkyl-modified dendritic DMAP catalyst could be easily recycled via phase separation which was induced by cooling the temperature from 60 °C to room temperature. The corresponding Baylis–Hillman adducts were obtained in good yields and the recycled and reactivated dendritic catalyst almost gave the same results.

Journal ArticleDOI
TL;DR: The Stork-Jung vinylsilane reagent is prepared in two steps and in good overall yield, which provides rapid and efficient access to a useful methyl vinyl ketone surrogate.
Abstract: The Stork-Jung vinylsilane reagent (1) is prepared in two steps and in good overall yield. This provides rapid and efficient access to a useful methyl vinyl ketone surrogate.

Journal ArticleDOI
TL;DR: In the aza-Morita-Baylis-Hillman reaction of N-sulfonated imines with methyl vinyl ketone (MVK) promoted by chiral phosphine Lewis base: (R)-2'-diphenylphosphanyl-[1,1']binaphthalenyl-2-ol (LB1) (10 mol %), the acolytic adducts were obtained in good yields with high ee.
Abstract: In the aza-Morita-Baylis-Hillman reaction of N-sulfonated imines with methyl vinyl ketone (MVK) promoted by chiral phosphine Lewis base: (R)-2'-diphenylphosphanyl- (1,1')binaphthalenyl-2-ol (LB1) (10 mol %), the aza-Morita-Baylis-Hillman adducts were obtained in good yields with high ee (70-94 % ee) at -30 °C in THF. The scope and limita- tions of this reaction have been disclosed.

Journal ArticleDOI
TL;DR: In this article, the enolate ion of methyl vinyl ketone was used to synthesize 5-hydroxy-3-phenyl-5-vinyl-2-isoxazoline, which was then quantitatively obtained by dehydration-aromatization under acidic conditions.

Journal ArticleDOI
TL;DR: In this paper, fair yields and enantiomeric excesses up to 91% were obtained in the Michael addition of cyclohexanone-2-carboxylate to methyl vinyl ketone, using (R,R)-trans-1,2-diaminocyclohexane as chiral auxiliary (37% mol/mol with respect to the donor).

Journal ArticleDOI
TL;DR: In this paper, a mechanistic rationalization of the obtained results in terms of electronic, steric and secondary interactions is proffered, and a loss of regioselectivity is observed with methyl vinyl ketone and methyl acrylate, due to intervention of HOMO-dipole-LUMO-Dipolarophile interaction.

Journal ArticleDOI
TL;DR: It was found that both the used Lewis base and solvent can significantly affect the reaction and the double aza-Baylis–Hillman adduct 3 exclusively in moderate to good yields with excellent diastereoselectivities.

Journal ArticleDOI
TL;DR: Several strategies for the immobilization of a L-valine-derived auxiliary on a Merrifield resin and on poly(ethylene glycol) are reported in this article, where the latter is shown to work excellently in asymmetric copper(II)-catalyzed Michael reactions of cyclic β-oxo esters 2 with methyl vinyl ketone (4), yielding the corresponding addition products 5 with quaternary stereocenter in selectivities of 97-99

Journal ArticleDOI
TL;DR: The resonance model, traditionally employed to explain the reactivity of these compounds, is not in line with the total atomic charges and DIs calculated by both methodologies, but the calculated values indicate that the pi population delocalizes only to a small degree.
Abstract: Atomic charges and delocalization indexes (DIs) for a series of carbonyl compounds comprising dimethyl ketone, acetaldehyde, acetic acid, methyl acetate, acetamide, methyl vinyl ketone, divinyl ket...

Journal ArticleDOI
TL;DR: The observed second-order rate constants of the Sc(OTf)3-catalyzed Diels-Alder reactions of anthracenes with MVK are by far larger than those expected from the observed linear Gibbs energy relation for the Diels (Alder) reactions of Anthraxenes with stronger electron acceptors than MVK, which are known to proceed via electron transfer.
Abstract: Rates of Diels-Alder cycloadditions of anthracenes with methyl vinyl ketone (MVK) are accelerated significantly by the presence of scandium triflate [Sc(OTf)3]. Sc(OTf)3 also promotes photoinduced electron-transfer reactions from various electron donors to MVK significantly. Comparison of the promoting effect of Sc(OTf)3 in photoinduced electron-transfer reactions of MVK with the catalytic effect of Sc(OTf)3 in the Diels-Alder reaction of 9,10-dimethylanthracene with MVK has revealed that the MVK-Sc(OTf)3 complex is a reactive intermediate in both the Diels-Alder and photoinduced electron-transfer reactions. The observed second-order rate constants of the Sc(OTf)3-catalyzed Diels-Alder reactions of anthracenes with MVK are by far larger than those expected from the observed linear Gibbs energy relation for the Diels-Alder reactions of anthracenes with stronger electron acceptors than MVK, which are known to proceed via electron transfer. This indicates that the Sc(OTf)3-catalyzed Diels-Alder reactions of anthracenes with MVK does not proceed via an electron-transfer process from anthracences to the MVK-Sc(OTf)3 complex.

Journal ArticleDOI
TL;DR: The results suggest that the first stage of the studied reaction is the generation of the base (the methoxide anion) with the help of trialkylphosphine, and the second stage is the hydroalkoxylation of the methyl vinyl ketone catalyzed by this base.
Abstract: The mechanism of phosphine-catalyzed hydroalkoxylation of the methyl vinyl ketone has been investigated by the second-order Moller−Plesset perturbation theory and the conductor-like polarized continuum model. The free energy reaction profiles of the reaction in both gas phase and solution phase are explored and compared. Our results suggest that the first stage of the studied reaction is the generation of the base (the methoxide anion) with the help of trialkylphosphine, and the second stage is the hydroalkoxylation of the methyl vinyl ketone catalyzed by this base. In the first stage, trialkylphosphine first adds to the methyl vinyl ketone to form a phosphonium enolate intermediate and then this species deprotonates a methanol molecule to generate a methoxide anion. Both steps involve free energy barriers of about 20 kcal/mol. In the second stage, both the addition of the methoxide anion to the methyl vinyl ketone and the proton transfer process from methanol to the methoxyl enolate anion intermediate ha...

Journal ArticleDOI
TL;DR: Condensation of enol ether with methyl vinyl ketone led easily to ketoaldehyde 7 whose cyclisation afforded the azaspiranic enone 8, a key intermediate for the synthesis of the title alkaloids as discussed by the authors.

Journal ArticleDOI
TL;DR: In this paper, the synthesis of N-substituted (3-oxobutanyl) carbamates via the tandem condensation of primary amines with methyl chloroformate, followed by the conjugate addition of the resulting carbamate with methyl vinyl ketone in the presence of Sn4+ modified zeolite Hβ (Hβ-SnA) at room temperature is described.